Whoops, I didn't mean to send that previous half formed mail :) Sorry. On Thu, Feb 19, 2009 at 08:38:38AM -0500, Justin Piszcz wrote: > > I was curious if anyone had done any benchmarks and/or has conclusive > information, what is the best Linux scheduler to use with SSDs? > > Noop? > CFQ? > AS? > Deadline? As mentioned in another mail there was a discussion on http://lkml.org/lkml/2009/1/31/28 and long thread talking about the introduction of the rotational flag here http://lkml.org/lkml/2009/1/5/340 . Cheapo SSDs or even USB keys are not auto detected as non-rotational devices by the kernel and after a bit of poking about I've come up with the following udev rules for my particular cases: SUBSYSTEM=="block", TEST=="/sys$devpath/queue/rotational", ATTRS{model}=="ASUS-PHISON *", RUN+="/bin/sh -c 'echo 0 > /sys$devpath/queue/rotational'" SUBSYSTEM=="block", TEST=="/sys$devpath/queue/rotational", ATTRS{idVendor}=="0951", ATTRS{idProduct}=="1606", RUN+="/bin/sh -c 'echo 0 > /sys$devpath/queue/rotational'" SUBSYSTEM=="block", TEST=="/sys$devpath/queue/rotational", ATTRS{manufacturer}=="SanDisk", ATTRS{product}=="Cruzer Micro", RUN+="/bin/sh -c 'echo 0 > /sys$devpath/queue/rotational'" Ever since the rotational option appeared I've been trying cfq but prior to that I was using noop or deadline. However it doesn't look like anyone has sat down and run the numbers to see what affect the ioscheulder/rotational flag is having on cheapo SSDs - all the suggestions are anecdotal. Could you run some benchmarks with these different options and report back the results? -- Sitsofe | http://sucs.org/~sits/ -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
